ROS 



ROT 



ROOT. " That part of the central 

 axis of a plant whicli is formed by 

 the dt'scenilmg fil)ros, and whose 

 function is to attract li(juid food from 

 tiic soil in which it. is mingled. It 

 differs from the stem in not having 

 leaves or buds upon its surface, and 

 in its tendency to burrow under 

 ground, retreating from light ; nev- 

 ertheless, some kinds of roots are ex- 

 clusively (ornied in air and light, as 

 in the ivy, and other such plants." 



Roots are of various figures, as 

 fibrous ; spindle, as in the radish ; 

 knotted, &c. The rhizome of the 

 flag and the tuber of the potato are 

 not roots, but subterranean stems. 

 Tlie cormus of palms and aroidae is a 

 mere expansion of tissue, which is 

 neither a root nor stem. 



ROOT CROPS. Crops of beets, 

 turnips, carrots, &c. 



ROOT STOCK. The rhizome of 

 the flag, ginger, arrow-root. 



ROSACE.E. "A large and im- 

 portant natural order of plants, the 

 species of which are, for the most 

 part, inhabitants of the cooler parts 

 of the world. Tliey are in some ca- 

 ses trees, in others shrubs, and in a 

 great number of instances herba- 

 ceous perennial plants : scarcely any 

 are annuals. No natural orders con- 

 tain more species of general interest, 

 in the beauty of their flowers or their 

 perfume : there is the rose itself, and 

 various species of the genera Rulus, 

 Spiiaa, FoUntUla, Gcum, and Pi/rus. 

 The apple, pear, plum, cherry, peach, 

 nectarine, apricot, raspberry, straw- 

 berry, and similar valuable fruits, are 

 the produce of others. As medicinal 

 plants, some are of consideralile im- 

 portance. Prussic acid is obtained 

 from the leaves and seeds of the bit- 

 ter almond, peach, plum, and other 

 species. This important assemblage 

 of plants is distinguished by havnig 

 several petals ; separate carpels ; dis- 

 tinct, perigynous, numerous stamens ; 

 alternate leaves, and an exogenous 

 mode of growth."' 



ROSE. The genus Kosa, which, 



by cultivation, has been extended to 



upward of a thousand varieties. They 



require a good loamy soil, and are 



66S 



much improved by judicious pruning. 

 .Many diseases infect the rose bhrul)s ; 

 of these, the aphm is the most com- 

 mon. They are also attacked with 

 blight, and by the rose-bug, a coleop- 

 terous insect, of the family of the 

 cockcliaflers. But by proper clean- 

 ing, and syringing with water, or 

 with tobacco water, the plants are 

 easily preserved in health. Several 

 varieties are worthy of cultivation for 

 the perfume (ullar) distilled from their 

 petals. The French rose is used by 

 druggists. 



ROSEBAY. The handsome Rho 

 dodcndron maximum. 



ROSE BUG. Insects of the same 

 family as the cockcliaffer, infesting 

 the rose, vine, and fruit-trees during 

 June and July. The perfect insect 

 issues from the earth in June, to 

 which the female retires at the end 

 of July and lays her eggs. They 

 cannot be destroyed except by direct 

 violence, fumigations and washes be- 

 ing of little service. The most usual 

 means is to catch them by the hand, 

 or by shaking the plants they infest, 

 and burning or crushing them. The 

 insects pass through all their trans- 

 formations in one year in the soil, 

 and emerge only in the beetle form. 



ROSEMARY. Rosmarinus offici- 

 nalis. A handsome evergreen shrub, 

 cultivated lor its odoriferous leaves, 

 from which an essential oil is distill- 

 ed. It requires a dry soil, and lasts 

 many years. 



ROSIN. The resin remaining 

 after distilling the spirit from turpen- 

 tine. Colophony. 



ROSTELLUM. The name given 

 to the retractile sucking tube of ap- 

 terous insects. 



ROT. A fatal disease of stock, 

 especially Sheep, which see. 



ROT "in WOOD. See Dry Rot 

 and Preservation of Timber. 



ROTATION OF CROPS. "As 

 crops of the cultivated plants succeed 

 to each other upon the same ground, 

 a question to be determined is the 

 order in which the different kinds 

 should follow each other. 



"All plants which are cultivated, 

 and which are carried from the ground 



